1. Field of the Invention
The present invention relates to a data transmission device, a data reception device, a data transmission method, and a data reception method.
2. Description of the Related Art
In recent years, a digital interface such as a High Definition Multimedia Interface (HDMI) has become widespread as a communication interface via which image or voice data is transmitted at a high speed from a source device to a sync device. As a source device, there are given, for example, a game player, a Digital Versatile Disc (DVD) recorder, a set-top box, and other Audio Visual (AV) sources. As a sync device, there are given, for example, a television set, a projector, and other displays. The HDMI standard is described in details in High-Definition Multimedia Interface Specification Version 1.4, Jun. 5, 2009, for example.
Further, a source device, such as a set-top box, receives video data as well as closed caption data from a satellite in some cases. Closed Captioning is a technique of displaying captions on a television screen; the technique has been approved by U.S. federal communications commission and standardized in the United States to enable a hearing-impaired person or a person with a hearing loss to enjoy a TV broadcasting program or a video. Closed captioning is standardized as a Digital Television Closed Captioning (DTVCC) in CEA-708.